An unidentified airport worker was filmed punching a male passenger, who was holding a baby, on July 29 in Nice, France (video below).
The British passenger was one of many waiting during a 13-hour flight delay for an EasyJet flight, according to The Sun.
Passengers were waiting to board a flight from Nice to London when the alleged incident happened.
French authorities have launched an investigation, which may include extraditing the U.K. passenger back to France.
"Both men have been caught on [closed-circuit TV] fighting," a source close to the investigation told The Sun. "The passengers appears to be responsible for the first physical contact, but the matter is still under investigation."
A witness said the passengers had been directed into a tunnel to board the plane, but found the other end of the tunnel blocked. After the passengers waited for 30-40 minutes, they went back to an airport lounge.
The witness said the Nice airport worker was "smiling at this guy, not helping him," and knocked the passenger's phone to the floor when the passenger attempted to take a picture because France has laws against taking pictures of officials at airports.
In a video filmed by a witness, the passenger pushed the airport worker, who came back with a punch while the passenger was holding a baby at his hip.
Bystanders and airport workers reportedly had to separate the two men, and police were called to the scene.
Right before the men exchanged blows, a female passenger shouted at the airport worker: "This is a disgrace. We have children, babies, screaming, no [diapers], no food. What are you smiling at?"
In addition to the video, a picture was taken of the incident by passenger Arabella Arkwright and posted on social media.
Arkwright told The Telegraph the wife of the passenger who was punched had complained to airport staff:
The couple were showing some irritation, which was perfectly understandable in the circumstances, but she was not threatening and was just saying "we've got children" which is quite a normal thing to say.
Then suddenly this man lunged at him and whacked him. My husband was standing beside them took the man to one side and the the police arrived and both of them were taken away.
We said "we're not not leaving without him" and later when he was returned to the plane, I'm pretty sure everybody on board applauded.
In response to the incident, EasyJet issued a statement:
EasyJet is very concerned to see this picture and can confirm the person in the photo is not an easyJet member of staff and they do not work for EasyJet's ground handling agents in Nice. We are urgently taking this up with Nice Airport and their special assistance provider Samsic, who we understand the person photographed works for.